* Dave Hansen <[email protected]> wrote:
> == FEATURE OVERVIEW ==
>
> Memory Protection Keys for Userspace (PKU aka PKEYs) is a CPU
> feature which will be found in future Intel CPUs. The work here was
> done with the aid of simulators.
>
> Memory Protection Keys provides a mechanism for enforcing page-based
> protections, but without requiring modification of the page tables
> when an application changes protection domains. It works by
> dedicating 4 previously ignored bits in each page table entry to a
> "protection key", giving 16 possible keys.
>
> There is also a new user-accessible register (PKRU) with two
> separate bits (Access Disable and Write Disable) for each key. Being
> a CPU register, PKRU is inherently thread-local, potentially giving
> each thread a different set of protections from every other thread.
>
> There are two new instructions (RDPKRU/WRPKRU) for reading and
> writing to the new register. The feature is only available in
> 64-bit mode, even though there is theoretically space in the PAE
> PTEs. These permissions are enforced on data access only and have
> no effect on instruction fetches.
So I'm wondering what the primary usecases are for this feature?
Could you outline applications/workloads/libraries that would
benefit from this?
Thanks,
Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
